Supports for centrifugal fans



P 3, 1966 A. H. LOEHR, JR

SUPPORTS FOR CENTRIFUGAL FANS 5 Sheets-Sheet 1 Filed Dec. 10, 1964 L3" we n n n w n. n v" mwm om F n 2 u 44 W u INVENTOR= ALBERT H. LOEHR,JR. BYW v fag-M ATTORNEY Sept. 13, 1966 R, JR 3,272,428

SUPPORTS FOR CENTRIFUGAL FANS Filed Dec. 10, 1964 3 Sheets-Sheet 2 ll SI" 1 w |NVENTOR= ALBERT H. LOEHR,JR.

BYW (7W ATTORNEY Sept. 13, 1966 Filed Dec. 10, 1964 A. H. LOEHR, JR 3,272,428

SUPPORTS FOR CENTRIFUGAL FANS 5 Sheets-Sheet 3 |NVENTOR= ALBERT H. LOEHR,JR. BYQ {1W ATTORNEY United States Patent 3,272,423 SUPPORTS F01? CENTRIFUGAL FANS Albert H. Loehr, Jr., Westwood, Mass., assignor to Westinghouse Electric Corporation, Pittsburgh, Pa, a corporation of Pennsylvania Filed Dec. 10, 1964, Ser. No. 417,421 20 Claims. (Cl. 230-128) This invention relates to centrifugal fans designed to handle highly heated gases, and relates more particularly to flexible supports for the casings of such fans.

It is common practice to support the rotors of induced draft fans on shafts in bearings on pedestals, and to bolt the casings to base angles embedded in concrete. When such fans handle highly heated gases such as flue gases of pressurized boilers employing gas recirculation, they may be heated to as high as 900 F. The rotors and casings of such fans expand differently due to differences in geometry, so that the rotors and gas inlets are not maintained in alignment resulting in aerodynamic losses; mechanical troubles may develop from inlet and seal rubs causing rough running, and expansion of the base angles may cause cracking of concrete foundations.

In an attempt to overcome such troubles, a so-called center line support patterned after central station turbine center line supports, has been used. Such a support has stiff pedestals, machined surfaces, keys and keyways at the tops of the pedestals and the bottoms of the brackets that support the casing, for permitting side movement of the casing in opposite directions during expansion and contraction so as to maintain the casing in axial alignment with the rotor. Disadvantages of such a support are that the pedestals and foundations have had to be strengthened, the fan casings have had to be heavily braced, and the machined surfaces have been expensive, resulting in heavy, expensive structures and requiring excessive floor space which is not available in some locations.

This invention has all of the advantages of such a centerline support, and overcomes its drawbacks by using an elastic support system. This system includes four elastic columns, one at each corner of the fan assembly, to support the weight of the casing, and includes two, tangential elastic radius rods to keep the casing vertical centerline centered. The casing, including two inlet boxes, and a scroll-shaped casing between the inlet boxes, is a rigid body, and is supported by extending four, generally parallel sheets, two of which form the outer ends of the inlet boxes, and the other two of which are the end sheets of the scroll-shaped casing which also form the inner ends of the inlet boxes, outwardly, and welding them to a pair of ship channels extending the length of the assembly parallel to the axis of the fan shaft. The two channels have identical support assemblies, each including a matching channel, two base plates, and two elastic columns.

An object of this invention is to improve the supports of the casings of fans handling heated gases.

This invention will now be described with reference to the annexed drawings, of which:

FIG. 1 is an end view of a double-inlet, centrifugal fan embodying this invention;

FIG. 2 is a side view of one side of the fan;

FIG. 3 is a side view of the opposite side of the fan;

FIG. 4 is a plan view looking at the top of one of the horizontally extending channels of FIGS. 13;

FIG. 5 is an enlarged section on the lines 5-5 of FIG. 2, and FIG. 6 is an enlarged section on the lines 66 of FIG. 2.

A double-inlet, induced draft fan such as is disclosed generally in the US. patent of H. F. Hagen, No. 1,846,-

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863, has a generally rectangular, in outline, inlet box 11 on each side of a scroll-shaped, inner casing 12. The inlet boxes 11 have inlets 13, and the scroll-shaped casing 12 has a tangential outlet 14. End sheets 17 of the inlet boxes 11 have portions 18 which extend outwardly beyond sides 19 of the inlet boxes, and have portions 20 which extend outwardly beyond opposite sides 21 of the inlet boxes. The sheet portions 18 extend normal to and are welded to the upper and inner sides of a channel 22 which extends horizontally at about the axis of shaft 23 at one side of the fan. The sheet portions 20 extend normal to and are welded to the upper and inner sides of a channel 26 aligned with the channel 22, and which is on the opposite side of the fan from the channel 22. The scroll-shaped casing 12 has vertically extending end sheets 27 which also form the inner sides of the inlet boxes 11, and which have portions 28 which extend outwardly beyond the casing 12, and which are welded to the top and inner sides of the channel 22.. The end sheets 27 have opposite portions 29 welded to the top and inner sides of the channel 26. A gusset 33 is welded to the inner side of the channel 22, to the inlet box sides 19 and to the casing 12. A gusset 36 is welded to the inner side of the channel 26, to the inlet box sides 21 and to the casing 12.

The sheet portions 18 and 20, while they are not exactly vertical, can be said to be roughly parallel to the vertical sheet portions 28 and 29. The sheet portions 18, 20, 28 and 29 rigidly attach the inlet boxes 11, and the scroll-shaped casing 12 to the channels 22 and 26.

The channels 22 and 26 are supported on similar, inverted channels 30 and 31 respectively. The channels 22 and 36 are bolted together at their centers by bolts 40, shown by FIG. 6, extending through holes 41 shown by FIG. 4. The channels 26 and 31 are similarly bolted together. The channel 36 has oblong holes 42 in its end portions, through which extend bolts 43 for attaching the ends of the channel 30 to corresponding ends of the channel 22 while permitting some sliding motion when expansion occurs as will be described later. The ends of the channel 31 are similarly attached to corresponding ends of the channel 26.

The channel 30 is welded at its ends to the upper ends of vertically extending, relatively flexible, steel plates 45. Gussets 46 are welded to the channel 30 and to opposite sides of the upper ends of the plates for preventing fatigue failure at the welds of the plates 45 to the channel 30. The lower ends of the plates 45 are welded to base plates 47. Gussets 48 are welded to the plates 47 and to opposite sides of the lower ends of the plates 45 for preventing fatigue failure at the welds of the plates 45 to the plates 47. The plates 45 have intermediate portions clamped between stiffening channels Sil and which are attached thereto by rivets 51. The plates 45 have inner portions 45a which extend upwardly at angles of 45 from near their bottoms, and which have upper portions clamped between lower portions, of channels 53, their upper ends being shown at 54. The channels 53 are attached to the plate portions 45:! by rivets 52.

The channel 31 is welded at its ends to the upper ends of vertically extending, relatively flexible, steel plates 65. Gussets 66 are welded to the channel 31 and to opposite sides of the upper ends of the plates for preventing fatigue failure at the welds of the plates 66 to the channel 31. The lower ends of the plates 65 are welded to base plates 67. Gussets 68 are welded to the plates 67 and to the opposite sides of the bottoms of the plates 65 for preventing fatigue failure at the welds of the plates 65 to the plates 67. The plates 65 have intermediate portions clamped between stiffening channels 70 and which are attached thereto by rivets 71. The plates 65 have inner portions 65a which extend upwardly at angles of from near their bottoms, and which have upper portions clamped between the lower portions of channels 73, their upper ends being shown at 74. The channels 73 are attached to the plate portions 65a by rivets 72.

The upper ends of vertically extending, relatively flexible, steel plates 55 are welded to the central portion of the channel 30. Gussets 56 are welded to the opposite sides of the upper ends of the plates 55 for preventing fatigue failure at the welds of the plates 55 to the channel 30. The plates 55 have outer portions 55a extending downwardly at 45 angles between the upper portions of the channels 53, their lower ends being shown at 57. The channels 53 are attached to the plate portions 55a by rivets 58.

The upper ends of vertically extending, relatively flexible, steel plates 75 are welded to the central portion of the channel 31. Gussets 76 are welded to the opposite sides of the upper ends of the plates 75 for preventing fatigue failure at the welds of the plates 75 to the channel 31. The plates 75 have outer portions 75a extending downwardly at 45 angles between the upper portions of the channels 73, their lower ends being shown at 77. The channels 73 are attached to the plate portions 75a by rivets 78.

On the floor of the apparatus room at opposite sides of the scroll-shaped casing 12, are aligned, concrete foundations 80. Attached to each foundation 80 by bolts 81 is the outer end of a relatively flexible, steel plate 82. The inner ends of the plates 82 are attached by bolts 83 to a common, inverted channel 84. The intermediate portion of each plate 82 is clamped between stiffening channels 85 and 86. The end sheets 27 of the scroll-shaped casing 12 have bottom portions 88 which are welded to the sides and bottom of the channel 84. The plates 82 are the previously mentioned radius rods.

The plates 45 are relatively flexible in directions towards and from the shaft 23, where they extend between the channels and the gussets 46. Likewise, the plates 65 are relatively flexible in directions towards and from the shaft 23, where they extend between the channels 70 and the gussets 66. Likewise, the plate portions 45a are relatively flexible in directions towards and from the shaft 23, where they extend between the gussets 48 and the channels 53. Likewise, the plate portions 65a are relatively flexible where they extend between the gussets 68 and the channels 73, in directions towards and from the shaft 23. Likewise, the plates a are relatively flexible in directions towards and from the shaft 23, where they extend between the gussets 56 and the channels 53. Likewise, the plates 75a are relatively flexible in directions towards and from the shaft 23, where they extend between the gussets 76 and the channels 73. The plates 45, 55, and 75 are relatively stiff in axial directions.

The flexible portions of the plates 45 and 55 permit thermal expansion and contraction of that portion of the fan casing that is on one side of the shaft 23, in directions normal to the axis of the shaft, while the flexible portions of the plates 65 and 75 permit thermal expansion and contraction of that portion of the fan casing that is on the opposite side of the fan shaft. Thus, expansion is in opposite directions on opposite sides of the fan shaft, and balances out, as does contraction, so that the inlet passages to the fan wheel or rotor, and the shaft seals, remain concentric with the shaft during thermal expansion and contraction.

The end portions of the plates 82 are relatively flexible so that their inner ends can rotate through small angles and permit slight vertical expansion and contraction of the casing.

The provision of the oblong holes 42 in the end portions of the channel 30, and similar holes in the end portions of the channels 31, permits sliding motion of such end portions along the end portions of the channels 22 and 26 in case the latter channels are the hottest, this axial sliding being counterbalanced about the midpoints of such channels where they are fixed together by the bolts 40.

Other advantages of this invention are that the elastic supports are many pounds lighter than prior supports; no machining of large flat areas is required; during thermal expansion there is no large friction force to cramp the housing or impose large forces on foundations so that the casing does not have to be so strongly braced, and less floorspace is required.

What is claimed is:

1. A centrifugal fan comprising a scroll-shaped inner casing, generally rectangular inlet boxes at opposite ends of said casing, said boxes having outer end sheets, said casing having end sheets forming the inner ends of said boxes, a first support member extending horizontally at one side of said fan, said sheets having portions extending outwardly to and attached to said member, a second support member in alignment with said first member at the opposite side of said fan, said sheets having portions extending outwardly to and attached to said second member, 21 third support member extending under and attached to said first member, a fourth support member extending under and attached to said second member, base support members under the ends of said third and fourth members, and flexible plates extending between said base members and said ends of said third and fourth members and attached to said base members and to said ends of said third and fourth members.

2. A fan as claimed in claim 1 in which said first and second members are structural channels, and in which said third and fourth members are inverted structural channels.

3. A fan as claimed in claim 2 in which means are provided for stiffening the intermediate portions only of said plates.

4. A fan as claimed in claim 3 in which said stiffening means are structural channels on opposite sides of said intermediate portions of said plates.

5. A fan as claimed in claim 1 in which means are provided for stiffening the intermediate portions only of said plates.

6. A fan as claimed in claim 5 in which said stiffening means are structural channels on opposite sides of said intermediate portions of said plates.

7. A fan as claimed in claim 6 in which said end sheets of said casing have portions extending downwardly below the bottom of said casing, in which a cross-member is provided between and attached to the bottoms of said last mentioned portions of said end sheets of said casing, in which a pair of additional base support members are provided at one side of said casing, and in which a pair of flexible plates are provided and attached at their outer ends to said last mentioned base support members, and attached at their inner ends to said cross-member.

8. A fan as claimed in claim 1 in which said end sheets of said casing have portions extending downwardly below the bottom of said casing, in which a cross-member is provided between and attached to the bottom of said last mentioned portions of said end sheets of said casing, in which a pair of additional base support members are provided at one side of said casing, and in which a pair of flexible plates are provided and attached at their outer ends to said last mentioned base support members, and attached at their inner ends to said cross-member.

9. A fan as claimed in claim 8 in which means are provided for stiffening the intermediate portions only of said last mentioned plates.

10. A fan as claimed in claim 9 in which means are provided for stiffening the intermediate portions only of said first mentioned plates.

11. A fan as claimed in claim 10 in which said last mentioned stiffening means are structural channels on opposite sides of said intermediate portions of said first mentioned plates.

12. A centrifugal fan comprising a scroll-shaped inner casing, generally recentagular inlet boxes at opposite ends of said casing, said boxes having outer end sheets, said casing having end sheets forming the inner ends of said boxes, a first support member extending horizontally at one side of said fan, said sheets having portions extending outwardly to and attached to said member, a second support member in alignment with said first member at the opposite side of said fan, said sheets having other portions extending outwardly to and attached to said second member, a third support member extending under and attached to said first member, a fourth support member extending under and attached to said second member, first base support members under the ends of said third member, second base support members under the ends of said fourth member, a first pair of flexible plates attached to said ends of said third member and to said first base support members, a second pair of flexible plates attached to said ends of said fourth member and to said second base support members, said plates of said first pair having bottom portions extending inwardly and upwardly towards the central portion of said third member, a flexible plate attached to said central portion of said third member and having bottom portions extending downwardly and outwardly in alignment with said bottom portions of said plates of said first pair, stiff means connecting said bottom portions of said plates of said first pair and said bottom portions of said plate attached to said central portion of said third member, said plates of said second pair having bottom portions extending upwardly and inwardly towards the central portion. of said fourth member, a flexible plate attached to said central portion of said fourth member and having bottom portions extending outwardly and downwardly in alignment with said bottom portions of said plates of said second pair, stiff means connecting said bottom portions of said plates of said second pair and said bottom portions of said plate attached to said central portion of said fourth member, stiff means extending in contact with opposite sides of intermediate portions only of said plates of said first pair, and stiff means extending in contact with opposite sides of intermediate portions only of said plates of said second pair.

13. A fan as claimed in claim 12 in which said first and second members are structural channels, and in which said third and fourth members are inverted structural channels.

14. A fan as claimed in claim 13 in which said stiff means are structural channels.

15. A fan as claimed in claim 12 in which said end sheets of said casing have portions extending downwardly below the bottom of said casing, in which a cross-member is provided between and attached to the bottoms of said last mentioned portions of said end sheets of said casing, in which a pair of additional base support members are provided at one side of said casing, and in which a pair of flexible plates are provided and attached at their outer ends to said last mentioned base support members, and attached at their inner ends to said cross-member.

16. A fan as claimed in claim 15 in which means are provided for stiffening the intermediate portions only of said last mentioned plates.

17. A fan as claimed in claim 12 in which a gusset is provided and attached to said first member and to the adjacent sides of said inlet boxes and of said casing, and in which another gusset is provided and attached to said second member and to the adjacent sides of said inlet boxes and of said casing.

18. A fan as claimed in claim 17 in which said first and third members are fixedly attached at their centers and slidably attached at their ends, and in which said second and fourth members are fixedly attached at their centers and slidably attached at their ends.

19. A fan as claimed in claim 12 in which said first and third members are fixedly attached .at their centers and slidably attached at their ends.

20. A fan as claimed in claim 1 in which said first and third members are fixedly attached at their centers and slidably attached at their ends.

References Cited by the Examiner UNITED STATES PATENTS 1,591,447 7/1926 Planck et a1. 230-128 2,018,827 10/1935 Avery 230-133 2,849,118 8/1958 Ashton 230-133 MARK NEWMAN, Primary Examiner.

H. F. RADUAZO, Assistant Examiner. 

1. A CENTRIFUGAL FAN COMPRISING A SCROLL-SHAPED INNER CASING, GENERALLY RECTANGULAR INLET BOXES AT OPPOSITE ENDS OF SAID CASING, SAID BOXES HAVING OUTER END SHEETS, SAID CASING HAVING END SHEETS FORMING THE INNER ENDS OF SAID BOXES, A FIRST SUPPORT MEMBER EXTENDING HORIZONTALLY AT ONE SIDE OF SAID FAN, SAID SHEETS HAVING PORTIONS EXTENDING OUTWARDLY TO AND ATTACHED TO SAID MEMBER, A SECOND SUPPORT MEMBER IN ALIGNMENT WITH SAID FIRST MEMBER AT THE OPPOSITE SIDE OF SAID FAN, SAID SHEETS HAVING PORTIONS EXTENDING OUTWARDLY TO AND ATTACHED TO SAID SECOND MEMBER, A THIRD SUPPORT MEMBER EXTENDING UNDER AND ATTACHED TO SAID FIRST MEMBER, A FOURTH SUPPORT MEMBER EXTENDING UNDER AND ATTACHED TO SAID SECOND MEMBER 